In a signal processing device including a plurality of signal processing units for performing signal processing including image signals, audio signals, and other signals, in order to detect whether a failure has occurred in any one of the signal processing units, generally it is necessary to stop signal processing, to allow a known signal such as a test pattern to be processed, and to make determination on the basis of whether a known processing result is output.
More specifically, generally in order to discriminate a failure in a circuit that continues signal processing, a technology for detecting whether there is a failure by first stopping image output, feeding a test pattern, and comparing with an expected value prepared in advance is proposed (see Patent Document 1).
Also proposed is a technology for detecting whether there is a failure by inserting a test image during a blank period and comparing with an expected value (see Patent Document 2).